What first comes to mind is the massive main gear. It's able to handle massive power from electric motors vs., the standard main gear with the E12. The E12 main gear is the same ID as the SG nitro machine. But I never had any issues with the E12 main gear.

With a solid search, JR still sells a conversion kit from the E12 to the ITO edition.

I learned the hard way using big electric motors on a Hirobo electric conversion kit.......